The president of Iran says the country has successfully enriched uranium for the first time. The key announcement is likely to increase tensions over Iran's nuclear program as a U.N. deadline approaches for Iran to end nuclear fuel enrichment.

Iranian President Mahmoud Ahmadinejad formally declared that Iran has "joined the club of nuclear countries."

"The laboratory-scale nuclear fuel cycle has been accomplished by our young generation of scientists," he added.

He said they have enriched uranium to the degree needed for nuclear power plants.

The announcement was met by cheers and chants of "Allahu Akbar," or "God is great," from an audience that included clerics and senior military commanders.

The timing of the announcement is seen as critical. The head of the U.N. nuclear watchdog agency, Mohamed ElBaradei, is expected to arrive in Tehran this week for talks aimed at resolving the standoff over Iran's nuclear aspirations.

The U.N. Security Council has told Iran to stop all nuclear fuel enrichment by April 28, just 15 days away.

In a nationally televised speech from one of Iran's holiest cities, Mr. Ahmadinejad said Iran's nuclear ambitions are peaceful and within the country's rights under international law. He rejected accusations by the United States and other Western nations that the country is seeking nuclear weapons.

He urged the West not to try to force Iran to abandon its nuclear program.

"I recommend that they not create everlasting hatred in the minds of the Iranian nation and the freedom-seeking nations of the world," he said.

Speaking before the Iranian president, the head of the country's nuclear program said Iran plans to expand its enrichment program to be able to use 3,000 centrifuges by the end of the year. Iranian officials say they are currently using 164 centrifuges.

The Iranian announcement was greeted with dismay by officials in Europe, the United State and Russia. The White House called it "moving in the wrong direction," but the State Department said the United States will continue to use diplomacy to change Iran's nuclear policy.